Spin Chemistry Investigation of Peculiarities of Photoinduced Electron Transfer in Donor–Acceptor Linked System

Magin, Ilya M.; Polyakov, Nikolay E.; Khramtsova, Ekaterina A.; Kruppa, Alexander I.; Stepanov, A. A.; Purtov, P. A.; Leshina, Tatyana V.; Tsentalovich, Yu. P.; Miranda, Miguel A.; Nuin, Edurne; Marín, M. Luisa

doi:10.1007/s00723-011-0288-3

Cited by 8 publications

(24 citation statements)

References 42 publications

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“…34,[37][38][39][40] This impact of polarity on CIDNP efficiency has been shown earlier for the photoinduced ET in the short dyad NPX -Pyr 4(a,b). 22,24 Dyads NPX-AA-Pyr 2(a,b) and NPX-CyAA-Pyr 3(a,b) also demonstrate the dependence of 1 H CIDNP effects at N-methylpyrrolidine fragments, obtained with the help of a pseudo-steady state pulses sequence, 41 on the solvent permittivity (Fig. 6, only (b)-diastereomers are shown).…”

Section: Cidnp Effects In (Rs)-and (Ss)-dyads and Their Relationshimentioning

confidence: 73%

“…Note that Scheme 1 differs from the scheme proposed earlier for the short 4(a,b) dyad. 23,24 In that scheme an exciplex is formed only from the local excited state but in our case, for 2(a,b) and 3(a,b), the leading edge of the exciplex's kinetic curves is satisfactorily fitted only if we assume the simultaneous formation of both the exciplex and local excited state. This forced us to assume the existence of at least two geometrical conformations of dyad molecules with quite different energies.…”

Section: Moreover the Exciplex Band Of 2(ab) Is Much Weaker Than Thamentioning

confidence: 81%

“…[19][20][21][22][23][24] Since the days of Jabotinsky's works, the photochemical generation of a pair of paramagnetic particles has been used for the modeling of biological processes such as the elementary steps of enzymatic oxygenation and drug-transport protein binding. [25][26][27] This approach is promising in several aspects.…”

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

“…[22][23][24] It should be noted that CIDNP is considered to be one of the most informative methods to identify short-lived paramagnetic particles, 28 and its use together with the fluorescence data can let one perform quantitative analysis of a process.…”

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

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Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Khramtsova

Sosnovsky

Ageeva

et al. 2016

Phys. Chem. Chem. Phys.

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The model reaction of photoinduced donor-acceptor interaction in linked systems (dyads) has been used to study the comparative reactivity of a well-known antiinflammatory drug, (S)-naproxen (NPX) and its (R)-isomer. (R)-or (S)-NPX in these dyads is linked to (S)-N-methylpyrrolidine (Pyr) using a linear or cyclic amino acid bridge (AA or CyAA), to give (R)-/(S)-NPX-AA-(S)-Pyr flexible and (R)-/(S)-NPX-CyAA-(S)-Pyr rigid dyads. The donor-acceptor interaction is reminiscent of the binding (partial charge transfer, CT) and electron transfer (ET) processes involved in the extensively studied inhibition of the cyclooxygenase enzymes (COXs) by the NPX enantiomers. Besides that, both optical isomers undergo oxidative metabolism by enzymes from the P450 family, which also includes ET. The scheme proposed for the excitation quenching of the (R)-and (S)-NPX excited state in these dyads is based on the joint analysis of the chemically induced dynamic nuclear polarization (CIDNP) and fluorescence data. The 1 H CIDNP effects in this system appear in the back electron transfer in the biradical-zwitterion (BZ), which is formed via dyad photoirradiation. The rate constants of individual steps in the proposed scheme and the fluorescence quantum yields of the local excited (LE) states and exciplexes show stereoselectivity. It depends on the bridge's length, structure and solvent polarity. The CIDNP effects (experimental and calculated) also demonstrate stereodifferentiation. The exciplex quantum yields and the rates of formation are larger for the dyads containing (R)-NPX, which let us suggest a higher contribution from the CT processes with the (R)-optical isomer.

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Section: Cidnp Effects In (Rs)-and (Ss)-dyads and Their Relationshimentioning

confidence: 73%

Section: Moreover the Exciplex Band Of 2(ab) Is Much Weaker Than Thamentioning

confidence: 81%

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

Section: Impact Of Chirality On the Photoinduced Charge Transfer In Lmentioning

confidence: 99%

See 2 more Smart Citations

Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Khramtsova

Sosnovsky

Ageeva

et al. 2016

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

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“…The commercial deuterated solvents for NMR spectroscopy: methanol The TR-CIDNP experiments were carried out using the following pulse sequence: radiofrequency (RF) saturation pulses-laser pulse-varied delay time (s)-RF detection pulse (1.5 ls about 50°)-free induction decay. The detailed description of our setup for TR-CIDNP detection can be found elsewhere [21]. The samples, sealed in a standard 5 mm Pyrex NMR tube, were irradiated by a Lambda Physik EMG-101 excimer laser (XeCl, wavelength 308 nm, output pulse energy up to 100 mJ) directly in the NMR probe.…”

Section: Chemicalsmentioning

confidence: 99%

Photoinduced Interaction of Atorvastatin with Acetophenone

et al. 2015

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The one of the most often prescribed preparation in the world, atorvastatin (ATR), lipid-lowering agent and antioxidant, is used for the prevention and treatment of atherosclerosis. At that the nature of its antioxidant activity is still unknown. This work presents the first example of the elementary mechanisms of ATR red-ox reactions, including the single electron transfer and the interaction with short-lived ketyl radicals. ATR reactivity has been investigated by means of the method of time-resolved chemically induced dynamic nuclear polarization (TR-CIDNP), nuclear magnetic resonance spectroscopy, ultraviolet spectroscopy, highperformance liquid chromatography, mass spectrometry and quantum chemical (DFT) calculations. To study the interaction of ATR with ketyl radicals in the solution acetophenone photolysis was used as a model reaction. It was shown that carbon atoms, belonging to the secondary alcohol groups of the dihydroxyheptane acid anion, are the reaction centers of ATR molecule in reactions with ketyl radicals. Because all statins have this fragment, one can expect that other statins could react with free radicals by this route. Thus, the proposed mechanism might be the one among several channels providing statins antioxidant activity.

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Configuration‐Dependent Photoinduced Electron Transfer in Diastereomeric Naphthalene‐Amino‐Naphthalene Triads

Nuin

Sastre

Pischel

et al. 2015

Chemistry A European J

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Novel diastereomeric triads containing two naphthalene chromophores have been designed in which an electron-donating amine moiety is covalently integrated into the connecting bridge. Photophysical studies (steady-state and time-resolved fluorescence) in solvents of different polarity have been performed. A remarkable stereodifferentiation in the intramolecular fluorescence quenching was found in acetonitrile. Laser flash photolysis gave rise to naphthalene-derived radical cations, which were also quenched by the amine with an even higher degree of stereodifferentiation. The results are in agreement with thermodynamic estimations and indicate that photoinduced electron transfer (PET) is the main quenching pathway. Furthermore, theoretical calculations have allowed us to explain the experimentally observed stereodifferentiation in PET quenching.

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Spin Chemistry Investigation of Peculiarities of Photoinduced Electron Transfer in Donor–Acceptor Linked System

Cited by 8 publications

References 42 publications

Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Impact of chirality on the photoinduced charge transfer in linked systems containing naproxen enantiomers

Photoinduced Interaction of Atorvastatin with Acetophenone

Configuration‐Dependent Photoinduced Electron Transfer in Diastereomeric Naphthalene‐Amino‐Naphthalene Triads

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